brooklynwx99

point proven

I haven't posted my thoughts on the upcoming pattern in a while, so here goes. I'm actually very optimistic about the state of affairs entering February for a variety of reasons, the most prominent ones being the superposition of the polar and subtropical jets and the Pacific jet extension. As of now, the pattern is pretty awful for snow due to a Pacific intrusion because of a strong, zonal polar jet. This has lead to a relatively snowless pattern with highly positive temperature anomalies throughout the CONUS. However, as we enter the 5 day range, the pattern will begin to shift as the Pacific jet extends. The ageostrophic flow in the left exit region of the jet streak will force an Aleutian low; this will then lead to a more meridional flow over the W US and displace some of the cold air locked over Alaska. The most important aspect of this pattern is the superposition of the STJ and the northern stream, as this will provide ample phasing opportunities as we move into February. The threat next weekend is a prime example of this feature. The Pacific jet looks to remain extended for the long-term, and this will lead to colder than average temperatures over the E US. Although there is still a highly positive EPO, the colder air from Alaska is still accessed via the +PNA. The STJ is still open for business during this time period; that feature along with the cold will provide ample storm opportunities from next weekend onward.

Personally, I think one of the more important factors is the system that pushes through before the SWFE. It has begun to trend in a more amplified direction in the last several runs: The heightened amplification of this feature leads to more CAA behind the system along with a more favorable NW-SE tilting of the 500mb flow. This, in turn, leads to a more favorable antecedent airmass for the SWFE: This system should be monitored closely. If it ticks more amplified yet again, then expect to see a colder run. This could be offset by a more amplified SWFE, but the lower heights in ahead of it due to the heightened CAA argue otherwise. Let's see how the 12z GFS plays out.

LMFAO

One more tick like that and things get real, real quick.

The 06z NAM, yet again, is more amplified and farther west, promoting higher heights over the EC. This should make another favorable jump.

GFS actually looks a bit more amplified with higher heights out front than the NAM through 12:

Part of the tick north is also due to vastly increased heights across the entire NE US, which is due to lessened confluence in SE Canada, less influence from the lobe around Michigan, and a slightly more amped, farther west trough. Again, it’s a big change for 24 hours out.

Wow, this is a really big tick given the short lead time. The trough is certainly more amplified and there’s more PVA as a result.

WOW. This changes everything. Amazing FGEN forcing along with an extremely vigorous 500mb vortmax. Let’s see what the GFS does.

The GFS OP is actually on the eastern edge of its ensemble spread, which has actually moved farther west from 18z. This is mostly in part to the entire trough/ridge couplet being more amplified from 18z:

Hey, I mean considering it’s our only decent shot for like 10 days gotta hop on it haha. Could be a nice little event but we’ll obviously have to see over the next few days.

Nice looking tracks on the GEFS, some of those members are 990s off E LI, would probably give some good results for coastal regions ala the 18z NAM. In fact, many members take the same track with higher intensity.

Lots of FGEN forcing here, which would lend itself to increased rates. Too early got talk specifics, obviously, but this is a welcome sight. The NAM also really digs the NS vort, which would most likely bring some added PVA into the region. Take it with a grain of salt, but it’s a really interesting run. Let’s see what the GFS does.

Look at the changes in the overall trough axis in response to the increased amplification of the ridge out west. Again, another tick and things get interesting. This isn’t far off.